This invention relates to burners, and more particularly it is concerned with a fuel gasifying burner in which kerosene or other fuel in a liquid state is formed into atomized particles and burned during the initial stages of combustion, after which the burner shifts from combustion of the fuel in the liquid state to combustion of the fuel in a gasified state following vaporization of the liquid fuel by the heat of its combustion.
In one type of fuel gasifying burner known in the art, kerosene or other liquid fuel is formed into atomized particles by the rotary action of a frustoconical rotary gasifying member and the liquid fuel in atomized particles is vaporized into a gasified state inside the rotary gasifying member by the heat of combustion of the liquid fuel in atomized particles. As the liquid fuel is vaporized into a gaseous state, air is mixed with the gaseous fuel into a fuel-air mixture which is vigorously ejected through a fuel-air mixture passage formed at the edge of an open end of the rotary gasifying member. In this type of burner, it is essential that the volume of the liquid fuel formed into atomized particles at initial stages of combustion be maximized to enable ignition and initiation of combustion of the liquid fuel to take place quickly and positively, and that flames of combustion of the fuel in a gaseous state formed at initial stages of combustion of the gaseous fuel be directed as much as possible to the rotary gasifying member from outside to efficiently heat the rotary gasifying member. It is also essential that the fuel in the gasified state produced inside the rotary gasifying member mix sufficiently with air into a mixture of fuel and air for sustaining combustion of the gaseous fuel. The aforesaid requirements should be met for reducing the time required for the burner to shift from combustion of the fuel in the liquid state to combustion of the fuel in the gaseous state and for producing a fuel-air mixture in a volume large enough to sustain combustion, so that combustion of the gaseous fuel can be maintained in a stable manner over a prolonged period of time. In addition, if the pressure under which flames of the mixture of fuel and air are ejected is too low at the time of combustion of the fuel in the gaseous state, gas in a gas chamber would be ignited and combustion might start in the gas chamber, making it impossible for the burner to function as a fuel gasifying burner. To avoid this trouble, it is usual practice to raise the pressure under which the flames of the fuel-gas mixture are ejected to a level which is free from the risk of causing combustion of the gaseous fuel due to backfire. This has tended to raise the noise of combustion of the gasified fuel and made it impossible to obtain combustion in soft flames in quiet atmosphere.
The problems described hereinabove have not satisfactorily been solved in the prior art. Thus the fuel gasifying burner of the type described has suffered the following disadvantages. Ignition and combustion of the liquid fuel would not sometimes take place in good condition, thus interfering with shifting of the burner to combustion of the gaseous fuel. The major portion of the flames of combustion of the gaseous fuel would be ejected toward the combustion cylinder and unable to heat the rotary gasifying member sufficiently to enable a perfect fuel-air mixture to be generated continuously within the rotary gasifying member. The noise of combustion of the gaseous fuel might reach an inordinately high level and cause environmental disruption.